Re: Practical boiling

["A.D. Karve" <adkarve@pn2.vsnl.net.in>]

  A few years ago we were approached by a voluntary agency working on rural
health problems to modify the design of our unbaked mud stove by adding a
cylindrical vertical cavity near the point of attachment of the chimney.  In
those days, a variety of liquids, that are now being sold in plastic
bottles, used to be sold in India in glass bottles of about 750 ml capacity.
Therefore these bottles were quite common in Indian households, even in the
rural areas. The cavity mentioned above was designed for accommodating such
a bottle filled with water. This water used to attain a temperature of about
80 degrees centigrade during the process of cooking.  The medical experts of
this voluntary agency told us that water could be sterilised by heating it
upto about 80 degrees and by keeping it at that temperature for some time.
This objective was achieved by the simple modification to our stove model.
This voluntary agency wanted to popularise this stove design with a view to
providing babies with sterile drinking water in order to avoid waterborne
diseases among infants. Later they told us that the incidence of waterborne
diseases among infants was dramatically reduced in those households that
adopted this stove.
However, this anecdote must be followed by another.  In Pune, the tap water
supplied to the city is filtered and chlorinated, but many householders,
including my own, have their own doubts about the integrity of the water
purification system, and therefore, they subject the drinking water to
further treatment. The University of Pune conducted a survey in which
householders in Pune city were asked if they drank tap water directly or if
they subjected the water to any further treatment before drinking it. The
second question was about the frequency of diarrhoeal attacks suffered by
members of the household during the previous year.  The results of this
survey showed that the persons who drank tap water directly suffered the
least from upset stomachs while the households that boiled their water
showed the highest frequency of such diseases.  Those who used various
filtering devices fell between the two groups. This showed that challenging
the body with small doses of pathogenic bacteria was necessary to keep the
immune system alert.
A.D.Karve

----- Original Message -----
From: Crispin <crispin@newdawn.sz>
To: Stoves <stoves@crest.org>
Sent: Saturday, January 12, 2002 9:08 PM
Subject: Practical boiling


> Dear Stovers with an interest in Boiling
>
> I have given this some thought and have come up with a practical use for
> rapid boiling.
>
> Every year we hear of some disaster or other where people are left without
> water supplies and they have to make do with what they can find.  They are
> always advise to boil their water before drinking it.
>
> In developing countries there is a constant need to purify water and
without
> real changes in service delivery, people have to boil water to purify it.
> This is going to become more of a problem in Africa in the near future
> because people who are HIV+ with HIV- babies are encouraged to use bottle
> feeding after 6 months.  This leads to all the problems that health
> professionals have been railing against for many years; in particular it
> gives babies bacteria that cause diarrhoea, dehydration and death.
Maternal
> health professionals have been fighting the baby formula people for
decades
> to get people to breastfeed their babies for 2 years.
>
> Now that HIV is so prevalent, there are serious reasons for encouraging
> people to go to bottle feeding especially after 6 months of age.  Before
> that, it has been shown, babies have a better chance of survival if they
are
> breastfed, even though there is a real chance of mother-to-child
> transmission of HIV in the process.
>
> You cannot have safe and successful bottle feeding without several things
> being in place, particularly two regimens: one for the water/formula
> preparation and the other for maintaining sterility of the nipples,
bottles
> and mixing vessls.
>
> These require treated or boiled water.  Boiling all water used in infant
> formula preparation is difficult and fuel consuming.  People do not do it
> properly because it is inconvenient, life is hard and they are probably
> already suffering from HIV/AIDS related conditions.
>
> The challenge to stovers all over the world is to prepare a technology
> package that will boil small amounts of water in a short time using as
> little fuel as possible.  This means that the combination of
> fuel+stove+water container must function as a package to deliver
> convenience, sterility, affordability and sustainability in terms of
> technology transfer and fuel type.
>
> Our competition should have a practical side so that our actions do not
> begin in words and end in words.  We should demonstrate a method of
> preparing water in sufficient quantity and of high enough purity to allow
a
> person living in a remote locality the ability to bottle-feed an infant
> safely.
>
> The water vessel must be 'open season'.  Anything that assists the stove
> developer to achieve the primary purpose is allowed.  The fuel has to be
one
> that can be made, collected, manufactured or is otherwise available in
> remote areas.  The stove should be able to be fired rapidly and boil a
> minimum quantity of water for a certain time period, to be established by
> health workers in the area.  Three minutes is a likely minimum, but some
> places have parasites that require longer boiling times - up to 20
minutes.
>
> Thus flash lighting and flash boiling are recommendable to meet the time
> constraints (adding convenience) but the boil must be maintained for a
> certain period so as to kill the biological contaminants.  The empahsis
> should be on system efficiency - i.e. minimum cost of fuel, or minimum
> quantity of fuel used, or minimum wealth loss in terms of time (given an
> 'opportunity cost' value) and material and minimum time taken.  The
stove's
> depreciation cost might also be factored in.
>
> Water purification kits are being distributed from the UK through Rotary
> programs and they cost UKPounds 40 each ($64).  I suggest this is too high
> for a practical stove-pot combination, however it could serve as an
initial
> guide.  Large numbers of the kits are given out each year so it is clearly
> in someone's interest to do so.  They work but they use purification pills
> which must be purchased ad infinitum.
>
> I suggest that we take the figure of US$50 (selling to the public price)
as
> the limit for any recommended technology combination (fuel+stove+pot) and
> that this be pursued by the Stove Group.
>
> The things that remain to be defined are the amount of water to be
boiled -
> which I recommend be 3 litres, and the time to be held at the local
boiling
> point - I recommend 3 minutes.
>
> I further recommend that the time taken to bring the water to a boil be
> rated separately from the fuel consumption rating.  This can be done by
> giving a distinct 'dimension' to the former by assigning a colour to
> different classes of speed, in the same way partical physicists do with
> sub-atomic bits and pieces.
>
> For example, the time taken to reach a boil can be rated in minutes:
>
> Under 2 minutes    Red
> 4 minutes    Orange
> 6 minutes    Yellow
> 8 minutes    Green
> 10 minutes  Blue
> 12 minutes  Ingido
> 14 minutes  Violet
> 14+minutes  Brown
>
> The rating of the stove's fuel consumption should be the grams of water
> boiled divided by the number of grams of fuel used to boil it for 3
minutes.
>
> 3000cc of water / 675 gm of fuel = 4.44
>
> Thus a stove that performs (brings the water to a boil) in 9.3 minutes and
> uses 560gm of wood to keep it boiling for 3 minutes rates as a "Wood
burning
> Blue 5.36"
>
> Those seeking a Red rating will struggle to get a low fuel use value, but
> there are customers for that class of product.  A claimed Green class
stove
> that runs badly on a particular day will find itself bumped into the Blue
> class where its fuel profligacy may work against it.
>
> This practical application offers many challenges to the stove makers.  It
> rewards rapid heating in the beginning, a high turndown rate, an efficient
> arrangement of fuel for initial combustion and an ability to stretch the
> fuels' heat yield into the final seconds.
>
> There is no real need to minimize the fuel load in the beginning as it is
> the fuel consumed _during_ the test that is important, thus removing the
> pursuit of unreasonable stove layouts specially designed to use tiny fuel
> loads for contest applications only.
>
> I believe this challenge is worthy of being met and that the rating method
> is durable and flexible enough to allow for dozens of different designs of
> stove, pot and fuel for many years into the future.
>
> Sincerely,
> Crispin
>
>
>
> -
> Stoves List Archives and Website:
> http://www.crest.org/discussion/stoves/current/
> http://www.ikweb.com/enuff/public_html/Stoves.html
>
> Stoves List Moderators:
> Ron Larson, ronallarson@qwest.net
> Alex English, english@adan.kingston.net
> Elsen L. Karstad, elk@wananchi.com www.chardust.com
>
> List-Post: <mailto:stoves@crest.org>
> List-Help: <mailto:stoves-help@crest.org>
> List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
> List-Subscribe: <mailto:stoves-subscribe@crest.org>
>
> Sponsor the Stoves List: http://www.crest.org/discuss3.html
> -
> Other Biomass Stoves Events and Information:
> http://www.bioenergy2002.org
> http://solstice.crest.org/renewables/biomass-info/
> http://solstice.crest.org/renewables/biomass-info/carbon.shtml
>
> For information about CHAMBERS STOVES
> http://www.ikweb.com/enuff/public_html/Chamber.htm
>
>


-
Stoves List Archives and Website:
http://www.crest.org/discussion/stoves/current/
http://www.ikweb.com/enuff/public_html/Stoves.html

Stoves List Moderators:
Ron Larson, ronallarson@qwest.net
Alex English, english@adan.kingston.net
Elsen L. Karstad, elk@wananchi.com www.chardust.com

List-Post: <mailto:stoves@crest.org>
List-Help: <mailto:stoves-help@crest.org>
List-Unsubscribe: <mailto:stoves-unsubscribe@crest.org>
List-Subscribe: <mailto:stoves-subscribe@crest.org>

Sponsor the Stoves List: http://www.crest.org/discuss3.html
-
Other Biomass Stoves Events and Information:
http://www.bioenergy2002.org
http://solstice.crest.org/renewables/biomass-info/
http://solstice.crest.org/renewables/biomass-info/carbon.shtml

For information about CHAMBERS STOVES
http://www.ikweb.com/enuff/public_html/Chamber.htm